Apparatus for processing a defect in an optical disc apparatus

Abstract

An apparatus for processing a defect includes a defect detection unit and a main filter. The defect detection unit detects a presence of a defect in a disc, and when the defect is detected, outputs a reset signal to the main filter. The main filter receives a focus error signal or a tracking error signal, which are digital signals, and outputs a focus regulation signal or a tracking regulation signal to regulate a focus or a tracking location of the disc by filtering the focus error signal or the tracking error signal. The reset signal is applied to the main filter and resets the signal values of a high-frequency component existing in the main filter to 0. Using the apparatus, a peaking phenomenon of the focus regulation signal or the tracking regulation signal can be removed and, accordingly, an accurate servo filter characteristic can be obtained.

1 . An apparatus for processing a defect, the apparatus comprising:
 a main filter;   a defect detection unit that detects a defect in a disc, and when the defect is detected, outputs a reset signal to the main filter; wherein   the main filter receives a focus error signal or a tracking error signal, which are digital signals, and outputs a focus regulation signal or a tracking regulation signal to regulate a focus or a tracking location by filtering the focus error signal or the tracking error signal,   wherein the reset signal resets signal values of a high-frequency component existing in the main filter to 0.   
   
   
       2 . The apparatus of  claim 1 , wherein the main filter resets the signal values of the high-frequency component to 0 when the reset signal is applied thereto, and outputs the focus regulation signal or the tracking regulation signal after removing the high-frequency component of the focus error signal or the tracking error signal. 
   
   
       3 . The apparatus of  claim 2 , wherein the main filter comprises:
 a high frequency gain filter that filters the focus error signal or the tracking error signal to have a high-frequency gain and then outputs the filtered focus error signal or the filtered tracking error signal;   a low frequency gain filter that filters the focus error signal or the tracking error signal to have a low-frequency gain and then outputs the filtered focus error signal or the filtered tracking error signal; and   an adder that outputs the focus regulation signal or the tracking regulation signal by adding an output of the high-frequency gain filter and an output of the low-frequency gain filter.   
   
   
       4 . The apparatus of  claim 3 , wherein the high-frequency gain filter operates in response to the reset signal when the defect is detected, and initializes signal values of the high-frequency component existing in the high-frequency gain filter to 0 when the reset signal is applied. 
   
   
       5 . The apparatus of  claim 2 , further comprising a digital to analog converter that receives the focus regulation signal or the tracking regulation signal from the main filter and then outputs the focus regulation signal or the tracking regulation signal after converting the focus regulation signal or the tracking regulation signal to an analog signal. 
   
   
       6 . The apparatus of  claim 3 , wherein the low-frequency gain filter filters the low-frequency component of the focus regulation signal or the tracking regulation signal, and controls the received focus regulation signal or the tracking regulation signal to pass only a low-frequency component of the focus error signal or the tracking error signal. 
   
   
       7 . The apparatus of  claim 5 , further comprising an analog to digital converter that is connected to a front terminal of the main filter and converts the focus error signal and the tracking error signal generated as analog signals to digital signals before outputting the focus error signal and the tracking error signal. 
   
   
       8 . An apparatus for processing a defect, the apparatus comprising:
 a main filter;   a defect detection unit that detects a presence of a defect in a disc and outputs a reset signal to the main filter when the defect is detected; and   the main filter receives a focus error signal or a tracking error signal, which are digital signals, and outputs a focus regulation signal or a tracking regulation signal to regulate a focus or a tracking location by filtering the focus error signal or the tracking error signal,   wherein the reset signal resets the signal values of a high-frequency component existing in the main filter to a predetermined offset value.   
   
   
       9 . The apparatus of  claim 8 , wherein the predetermined offset value is a value, that offsets the signal values of the high-frequency component existing in the main filter to be fixed to a uniform value and is specified by a user. 
   
   
       10 . The apparatus of  claim 9 , wherein the main filter resets an output value of the high-frequency component existing in the main filter to have the offset value when the reset signal is applied, and outputs the focus error signal or the tracking error signal after removing the high-frequency component of the focus error signal or the tracking error signal, leaving the offset value. 
   
   
       11 . The apparatus of  claim 9 , wherein the main filter comprises:
 a high-frequency gain filter that filters the focus error signal or the tracking error signal to have a high-frequency gain and then outputs the filtered focus error signal or the filtered tracking error signal;   a low-frequency gain filter that filters the focus error signal or the tracking error signal to have a low-frequency gain and then outputs the filtered focus error signal or the filtered tracking error signal; and   an adder that outputs the focus regulation signal or the tracking regulation signal by adding an output of the high-frequency gain filter and an output of the low-frequency gain filter.   
   
   
       12 . The apparatus of  claim 11 , wherein the high-frequency gain filter operates in response to the reset signal when the defect is detected and initializes the signal values of the high-frequency component existing in the main filter to the offset value when the reset signal is applied. 
   
   
       13 . The apparatus of  claim 9 , further comprising a digital to analog converter that receives the focus regulation signal or the tracking regulation signal from the main filter and then outputs the focus regulation signal or the tracking regulation signal after converting the focus regulation signal or the tracking regulation signal to an analog signal. 
   
   
       14 . The apparatus of  claim 9 , wherein the low-frequency gain filter filters the low-frequency component of the focus regulation signal or the tracking regulation signal and controls the received focus regulation signal or the tracking regulation signal to to pass only a low-frequency component of the focus error signal or the tracking error signal. 
   
   
       15 . The apparatus of  claim 13 , further comprising an analog to digital converter that is connected to a front terminal of the main filter and converts the focus error signal and the tracking error signal generated as analog signals to digital signals before outputting the focus error signal and the tracking error signal.